The present invention relates to an apparatus for drying, cooling and, directly thereafter, coiling or cutting into sheets of a paper web. More particularly, the invention relates to an apparatus which usually comprises in a straight line, a dryer, a cooler, a coiler and a cutter so that the web can either be wound up in a coil or transversely cut into sheets which can be stacked.
In paper web processing involving, for example, impregnation and/or coating the paper web after it has been impregnated or coated is dried in a heated condition and then is cooled. Depending upon the use it is either wound up into rolls or coiled directly or cut into sheets which are then stacked. Production lines of this type can include a dryer, cooler, coiler or roll winder and transverse cutter (sheet cutter) in a straight line.
Upon start up of the apparatus or after a tear in the web, the leading end of the paper web, which can have a width of say, 3 m and which is displaced with a speed of 50/m, is drawn through the dryer and the cooler and downstream of the cooler is engaged by service personnel and wound up or fed to a transverse cutter.
The leading end of the web, some 10 to 20 m, usually does not have the desired characteristics since the operating parameters of the dryer are usually not stabilized within this length. This portion is thus separated or lopped off and can fall as a waste upon the ground. The new leading end is placed by hand onto the coiler or the transverse cutter. For trained personnel this is usually not a difficult operation. However, because the coiler lies in the path of the web when the latter is to be fed to the transverse cutter, problems have been encountered. In such earlier systems economics are poor, substantial amounts of scrap or waste are created and the interruption in the paper feed can be substantial. DE 29 20 329 C3 describes an apparatus for drawing the paper web into a float dryer in which a transverse rod is displaced on a pair of endless traction elements like chains through the dryer and the cooler to draw the web through. The apparatus is provided with a multiplicity of rollers downstream of the dryer and the conveyor system allows the arrangement to operate with a nonstop coiler.
For guiding the chains, sprocket wheels are provided coaxial with the rollers and the mandrel. The paper web can run to a wind up star downstream of the cooler and to adhere the paper web to the winding sleeve on the mandrel, a pivot arm carrying a pressing roller and a blade shaft can be provided.
It is the principal object of the present invention to provide an apparatus for the drying, cooling and selectively, the winding up of the paper web or the transverse cutting of the paper web into sheets which can be stacked, whereby changeover between the coiling and cutting and, conversely, between sheet cutting and coiling is mechanized or automated and made more reliable.
Another object of this invention is to provide an apparatus which makes better use of operating personnel and, indeed relieves the personnel of the need for manual changeover.
Another object of the invention is to provide an apparatus of the type described which will produce significantly less waste.
These objects are attained by an apparatus for drying, cooling, coiling or sheet cutting of a paper web which comprises:
a dryer, a cooler, a coiler and a transverse cutter disposed in succession along a straight line in a path of a paper web, the coiler having at least one coiling mandrel adapted to be disposed in a winding-readiness position;
a conveyor for the paper web connected with the dryer and having one segment running from the cooler to the winding-readiness position and a further segment running from the one segment to the transverse cutter;
a lopping device proximal to the winding-readiness position for severing end portions from the paper web;
a deflector and pressing device for pressing the web onto a winding sleeve on the mandrel in the winding-readiness position, the further segment being shiftable between a position in which the web is discharged as waste and a position in which the web is fed to the transverse cutter; and
laterally guided traction elements engageable with a leading end of the web and extending from an inlet to the dryer and past the cooler to a web-path bifurcation downstream of the lopping device for entraining the web to the bifurcation from the inlet to the cooler.
According to the invention, at the upstream side of the first conveyor setting running in the region of the winding mandrel, a roller pair is disposed to engage the paper web in its nip, with one of the rollers being pressed against the other.
One of the two rollers may be rubber jacketed. The lopping device can, according to the invention be located beyond the roller pair. A guide roller can be arranged in the path of the web downstream of the lopping device.
According to another feature of the invention at the end of the conveyor segment proximal to the winding mandrel in its readiness position, a roller pair can be disposed with an adjustable spacing and at least one driven roller. A spray nozzle can be located between the cooler and an associated part of the conveyor system.
The second conveyor segment which ends in the region of the transverse cutter can have a belt conveyor whose outlet side is swingable about the axis of its rerouting roller from an active position in which its upstream end is directly adjacent another conveyor segment, into a passive position in which a clearance is provided with the conveyor segments so that discarded lengths of the paper web can be discharged. The conveyor according to the invention can comprise three segments of which a first passes the paper web over the coiler or the transverse cutter. The second segment is proximal to the mandrel in readiness and feeds the paper web in a tension state in the gap between the coiler and the transverse cutter. The third conveyor segment ends at the transverse cutter.
In the region of the mandrel in its readiness portion, the second conveyor segment can run vertically.
In the third conveyor segment, a belt conveyor can be provided upstream of another belt conveyor. The upstream belt conveyor can be operated at a speed which is substantially higher then the speed with which the paper web travels. In the readiness portion of the mandrel, the neighboring segment is either horizontal or inclined slightly downwardly. This segment can be formed by conveyor tables for the paper web which in their active positions at least in part lie within the range of mobility of the coiler and thus these tables are displaceable into inactive positions outside the range of mobility.
The conveyor segments include an inlet side conveyor table which in its active position practically reaches the mandrel in its readiness portion and is located at least approximately at the same height as the mandrel. The conveyor table at the outlet side, which is proximal to the mandrel, in its active position is located at most at the same height as the inlet side conveyor table. The inlet side of the conveyor table in its active position ends above the mandrel and the outlet side conveyor table in its active portion begins below the mandrel.
The inlet side conveyor table should be displaceable in the direction of the cooler and track. The outlet side conveyor table can be raised and lowered and the conveyor tables can be formed as belt conveyors. The conveyor tables can be float tables defining a planar surface which is easily formed from sheet metal and may be slightly inclined in the web travel direction.